Attachment structures in Rhizotrochus (Scleractinia): macro‐ to microscopic traits and their evolutionary significance. (4th January 2013)

• Record Type: Journal Article
• Authors: Tokuda, Yuki; Ezaki, Yoichi
• Is Part Of: Lethaia. Volume 46:Number 2(2013:Jun.)
• Page Start: 232
• Page End: 244
• Publication Date: 2013-01-04
• Subjects: Paleontology -- Periodicals; Geology, Stratigraphic -- Periodicals; 560
• DOI: 10.1111/let.12013
• Languages: English
• ISSNs: 0024-1164

Abstract

<abstract abstract-type="main" id="let12013-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Marine sessile benthic organisms living on hard substrates have evolved a variety of attachment strategies. <italic>Rhizotrochus</italic> (Scleractinia, Flabellidae) is a representative azooxanthellate solitary scleractinian coral with a wide geographical distribution and unique attachment structures; it firmly attaches to hard substrates using numerous tube‐like rootlets, which are extended from a corallum wall, whereas most sessile corals are attached by stereome‐reinforced structures at their corallite bases. Detailed morphological and constructional traits of the rootlets themselves, along with their evolutionary significance, have not yet been fully resolved. Growth and developmental processes of spines in <italic>Truncatoflabellum</italic> and rootlets in <italic>Rhizotrochus</italic> suggest that these structures are homologous, as they both develop from the growth edges of walls and are formed by transformation of wall structures and their skeletal microstructures possess similar characteristics, such as patterns of rapid accretion and thickening deposits. Taking molecular phylogeny and fossil records of flabellids into consideration, <italic>Rhizotrochus</italic> evolved from a common free‐living ancestor and invaded hard‐substrate habitats by exploiting rootlets of spines origin, which were adaptive for soft‐substrate environments.</p> </abstract>